IT WAS NICE OF THE registrar of voters to let me vote twice. Since changing residences almost a year ago, I'd not yet acquainted myself with the polling place in my new neighborhood, so I swung by San Jose's Burnett Middle School, where I'd voted many times before, to see if voting officials had processed my new registration, and if so, could direct me to my new polling place. As it turns out, I was still registered at the old address. What the heck, I figured, I would exercise my constitutional rights as an American at the old polling place. After all, it was still in the same legislative districts, so my ballot wouldn't contaminate any races with a stray vote.

I handed in my ballot, pocketed the numbered stub and pasted an "I Voted" sticker on my lapel. Next I stopped at the post office to check my P.O. box. To my surprise, a voter pamphlet with a new polling place had arrived. At this point, my journalistic curiosity took hold. I had heard about ballot stuffing, election rigging and dead people voting over the years but had no firsthand knowledge of vote stealing. Just how easy is it to steal a vote?

After thinking through the implications, I decided to test the system, and I drove over to San Jose Christian Bible College on South 12th Street to see if I was double-registered. I showed them my pamphlet. The friendly volunteer found me on the list and pushed a sheet across the table for me to sign. I may have raised some eyebrows when I decided to read the fine print at the top, which cautioned that it was illegal to vote twice or attempt to vote twice. Satisfied that I was not committing a felony, I signed by my name, just as I had done several hours earlier, and was handed a second ballot. In view of the voting officials, I marked the punch card "Ballot Refused," tore off the stub, and handed the card back to be placed in the ballot box.

While I did not cast two ballots, it would have been very easy to have done so. Somehow I wound up on the voter rolls twice. And it's not like my name's a common one--at least outside of several small towns in central Italy.

The Santa Clara County Registrar of Voters has much to recommend it--an informational telephone number answered by live humans, a community outreach program, a department head who returns media calls quickly and an excellent website, which would have allowed me to find my polling place by entering my home address in a web-based query form. It also would have advised me that under the "Motor Voter' law, I could have voted at my new polling place, since it was within the same county, even without re-registering.

When I checked the records the following day, a clerk informed me, politely, "You're registered twice, sir." She explained that since I had registered a day before the deadline, "we didn't have a lot of time for research. We're under the gun. The secretary of state wants to know our numbers."

Registrar Kathryn Ferguson assured me that "the system is actually programmed to catch duplicates." Her office processed "something like 7,000" registrations on the last day, and the computer kicked out 1,763 as "100 percent duplicates" and 1,354 "possible duplicates." Mine was among the latter because the form I had downloaded off the web did not have a space to indicate birthplace. Her office had not had a chance to manually inspect the possible dupes "because there were so many."

Ferguson, a former computer systems manager, programmer and registrar for counties in Nevada and Texas, came to Silicon Valley last year and inherited an office saddled with ancient, obsolete computers. "It's an old Data General system. I can't tell you how old it is," she sighs. She wants to replace that boat anchor with some modern hardware and software that will allow speedier processing of registrations and results, OCR scanning and better customer service.

Nonetheless, she declares "we look at every signature" after the election, and, since I had signed the rolls twice, "we would have caught you."

"And we do send that to the D.A.," she advises.

Hopefully, the supes will let Ferguson buy a computer system worthy of the world's technology capital. At least now we have a registrar who's computer savvy enough to look under the hood. Even with good systems, however, Ferguson concedes that a handful of intentionally fraudulent or inadvertent duplicate votes can slip through.

Receiving two ballots on election day gave me a direct look at just how easy it would be to vote twice--simply omitting a middle initial or birthplace prevents a computer match.